Tracheal tube

ABSTRACT

A tracheal tube comprises a hollow tube body having an open tube end and an inflatable sealing cuff disposed around the tube adjacent the tube end. At least one small diameter tube is associated with the hollow tube and it has a nozzle portion terminating in a discharge jet adjacent the open tube end for use in jet ventilation at high frequencies above 600 cycles per minute. The small diameter tube has a diameter of from between 0.4 to 0.05 × the inside diameter of the tube shaft and the outlet opening of the jet nozzle is arranged relative to the tube end either inside or outside the tube diameter at such a spacing that it is within ±5× the inside diameter of the tube body.

FIELD AND BACKGROUND OF THE INVENTION

This invention relates to tracheal devices in general and, inparticular, to a new and useful tracheal tube having a tube shaft withan inflatable sealing cuff arranged in the range of the proximal endwhich is connected to a feed line extending in the range of the wall ofthe tube shaft.

For purposes of ventilation and to enhance breathing, it is known to userespirators which permit high frequency positive pressure ventilation(HFPPV). While the frequency of the known respirators controlled by thebreathing rhythm is substantially in the normal physical range,breathing pulse sequence frequencies of up to 600 cycles per minute areused in HFPPV, with ratios of inspiration time to expiration time of 3:1to 1:5.

The supply of the pulsating ventilation gas can be effected in a knownmanner either over a tracheal tube (A. Jonzon, G. Sedin and U.Sjoestrand: Acta anaesth. Scand. Supply. 53, 23-26, 1973), or directlyover a catheter inserted into the trachea after puncturing the skin. (M.Klain, R. Brian Smith: "Critical Care Medicine", Vol. 5, No. 6, 280-287,1977).

In the last-mentioned jet ventilation, the ventilation of test animalswas effected at various ventilation rates from 20/cycles per minute to200 cycles per minute with a minute volume of 17 liter per minute. Theupper air passage remained in natural position without the insertedtracheal tube.

For effecting HFPPV, an insufflation and ventilation system is alsoknown (U. Sjoestrand: Acta anaesth. Scand., Supply. 64, 14-15, 1977)wherein a ventilation attachment was placed on the tube shaft of anendotracheal tube, from which an insufflation catheter projects into thetube shaft. The breathing resistance against the interior of theattachment can be adjusted over a variable throttle opening.

Difficulties are encountered in ventilation with the presently knowntracheal tubes if higher pulse sequence frequencies of the breathingpulses are to be used. The use of a jet catheter to supply theventilation gas, which either projects freely into a tracheal tube or isintroduced directly into the trachea, impairs the breathing considerablyby turbulence which hinders the return flow and outflow of exhaled CO₂.The reason lies in the aerodynamically unfavorable, or inadequatelyfixed and defined, position of the jet nozzle relative to the widelybranched hollow system of the lungs to be ventilated.

SUMMARY OF THE INVENTION

The present invention is based on the problem of designing a trachealtube so that it is particularly suitable for jet ventilation at highfrequencies. The effectiveness of the ventilating air supply to thelungs is to be improved, and favorable conditions are to be provided forthe elimination of the exhaled CO₂ at low flow resistances. This problemis solved by providing at least one jet nozzle for use of the trachealtube in jet ventilation at frequencies above 600 cycles per min. in theproximal end portion of the tracheal tube, whose diameter is between 0.4to 0.5 times the inside diameter of the tube, and that the outletorifice of the jet nozzle is arranged with regard to the proximal tubeend inside or outside the tube shaft in a spacing distance which iswithin five times the inside diameter of the tube shaft. It was found,surprisingly, that these dimensioning specifications must be strictlyobserved if satisfactory flow conditions and low, substantiallyturbulent-free flow resistances are to be achieved. In order to avoiduncontrolled position changes, the jet nozzle must be properly fixedrelative to the tube shaft.

Since the jet nozzle with its nozzle carrier and with the parts of thefeed line projecting into the interior of the tube could hinder theintroduction of other auxiliary instruments, such as suction probes,etc., a further advantageous development of the invention consists inthat the jet nozzle is elastically mounted with the parts of the feedline protruding into the interior of the tube in such a way that thecross-section of the tube can be cleared again to a great extent.Additional auxiliary instruments can thus be introduced unhinderedthrough the tube shaft. The reduced accessibility, caused by thedetachable accessories compared to a free tracheal tube, is thuscompensated to a great extent.

Though such a design seems generally advisable for detachableaccessories fixed in a tube, it was found that the elastic support is ofconsiderable importance when the above-described diameter or positionspecifications are to be realized for at least one jet nozzle in theproximal end portion of the tracheal tube. Since the jet nozzle must beproperly fixed to achieve a favorable flow and return flow arrangementwith regard to the interior of the tube shaft, this mostly results in abulky arrangement in the interior, which would hinder the introductionof auxiliary instruments.

Another important improvement is achieved by arranging two jet nozzlesspaced from each other, which are connected to separate feed lines. Suchan arrangement permits selective ventilation of the lungs by gascurrents adapted to the existing resistance conditions and the injury,respectively, (See J. M. Cavanilles; F. Garrigosa; E. Prist, J. R.Oncins: 7th Annual Scientific Symp. Soc. of Critical Care Medicine,Abstract 70, 1978). This design seems to be of particular advantage whenusing the given dimensioning specifications, but advantageously, it canalso be used outside this range within the framework of a selectiveventilation distribution circuit (SVDC). A favorable use of this nozzlearrangement is possible not only in the given frequency range above 600cycles per minute, but also in lower frequency ranges.

The jet nozzle is preferably arranged in the vicinity of the centralaxis of the tube shaft. This provides favorable spreading possibilitiesfor the issuing gas jet.

Since such a high-frequency ventilation must be carried out by means ofa controlled jet ventilating gas source, it furthermore seems advisableto provide an additional test line whose mouth, either on the nozzlecarrier, or in the range of the jet nozzle, is arranged upstream of thenozzle orifice, seen in the direction of the ventilating gas flow. Inthis position, the gas flow through the nozzle provides a certainshielding effect, which prevents clogging of the receiving opening ofthe test line.

The feed lines and the test line are preferably connected, at least insections, with the wall of the tube shaft. When made of an elasticplastic, for example, complete or partial incorporation of the lines inthe material of the tube shaft is advantageous.

For adaptation to the existing resistance conditions, it seems advisableif the jet nozzle has a variable cross-section. The variation can beachieved both by changing the nozzles or by varying the cross-sectionalarea of the nozzles.

Another important adjusting possibility in order to achieve optimumventilation conditions and low flow resistances consists in making thejet nozzle adjustable in the longitudinal direction of the tube shaft.By connecting control devices, the effect of the ventilation can thus bemonitored, and an optimum value can be set.

Accordingly, an object of the present invention is to provide a trachealtube which comprises a hollow tube shaft or body having an open tube endwith an inflatable sealing cuff disposed around the tube adjacent thetube end and which includes at least one small diameter tube associatedwith the hollow tube body, for example, by being embedded in the wallthereof, and which has a nozzle portion which terminates in a dischargejet adjacent the open tube end for use in jet ventilation at highfrequencies above 600 cycles per minute and, wherein, the small diametertube has a diameter of from 0.4 to 0.05 times the inside diameter of thetube body and that the outlet opening of the jet nozzle is arrangedrelative to the tube end either inside or outside the tube at a spacingsuch that it is within ±five times the inside diameter of the tube body.

A further object of the invention is to provide a tracheal tube which issimple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWING

In the Drawing:

FIG. 1 is a partial axial sectional view of a tracheal tube for use withhuman beings, constructed in accordance with the invention, andsubstantially in the natural size;

FIG. 2 is a view similar to FIG. 1 of another embodiment of theinvention, shown on a slightly enlarged scale; and

FIG. 3 is a view similar to FIG. 1 of still another embodiment of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawing in particular, the invention embodied therein,comprises, a tracheal tube, generally designated 1, for use with humanbeings, and having a longitudinal bore 20 which includes an open end 1e.FIG. 1 shows an endotracheal tube with a tube shaft 1 of an elasticplastic material. In the range of the proximal end of this tube, aninflatable sealing cuff 2 is arranged, which is connected to a feed line3 embedded in the wall of tube 1.

As shown, the open end 1e of the tube shaft lies in a plane obliquelyextending relative to the longitudinal axis of the tube shaft.

A feed line 4, which is also embedded in the wall of tube 1, projects inthe proximal range from the inner wall and forms a nozzle carrier 5whose outlet opening acts directly as a jet nozzle 6. Set back in thedirection of flow of the ventilating gas, a test line 7 with a mouth 8is arranged on nozzle carrier 5, for example, to monitor respiratorytrack pressure.

Jet nozzle 6 and mouth 8 of test line 7 are mounted properly and infixed position in the range of the center axis of the tube shaft 1 bysuitable selection of the material for the nozzle carrier 5.

The diameter of jet nozzle 6 is 1 mm, and is thus 0.09 times the insidediameter "a" of tube 1, which is fixed with 11 mm. The position of thejet nozzle determined by the distance "s" with regard to the proximaltube end 1e is -0.7a. In this embodiment, the jet nozzle is arrangedinside of tube 1. The corresponding position in a longitudinal directioncan be fixed, for example, by shortening the freely rising nozzlecarrier 5 whose outlet opening is jet nozzle 6. The diameter of testline 7 is substantially equal to the diameter of feed line 4 to jetnozzle 6, and to the diameter of feed line 3 to sealing cuff 2.

The part of feed line 4 serving as nozzle carrier 5, together with testline 7, is so elastic with regard to the wall fastening, that jet nozzle6 and the parts connected with it can be pushed aside, e.g., when asuction hose is introduced, so that the cross-section of the tube issubstantially cleared.

In the embodiment according to FIG. 2, two jet nozzles 9 and 10 areprovided which permit selective ventilation of the lungs. Overcorresponding sections of feed lines 14 and 15, which are used as nozzlecarriers 11 and 12, and which are displaceable in a holding part 13secured on the wall, it is possible to adjust jet nozzles 9 and 10 inthe longitudinal direction of tube 1 (jointly or individually). In somecases, it may be advisable to feed both jet nozzles 9 and 10 from acommon feed line. Greater adaptability is achieved, however, if separatefeed lines 14 and 15 are provided at least inside the tube or in itssurface range. Test line 7 terminates in the direction of flow of theventilating gas in front of the two jet nozzles 9 and 10 arranged fordivergent gas currents.

The prescribed variation range for the distance "s" of the jet nozzlesrelative to the proximal tube end is indicated in the drawing by +5a and-5a, where "a" denotes the inside diameter of the tube. In thisembodiment, jet nozzles 9 and 10, arranged in the vicinity of the centeraxis of the tube 1 or their nozzle carriers 11 and 12, as well as theparts of feed lines 14 and 15 and the test line can likewise bedeflected elastically toward the inner wall of the tube. The angulararrangement and longitudinal position of the two jet nozzles 9 and 10can be checked by a corresponding scale division on the outer wall ofthe tube.

FIG. 3 shows a simplified embodiment of the tracheal tube 1" with twojet nozzles 16 and 17, whose discharges are substantially within theplane of the open end, having feed lines 18 and 19 are arrangedcompletely inside the wall thickness of tube 1". Mouth 8 of test line 7is set back correspondingly on the inner wall surface of tube 1" in thedirection of flow of the ventilating gas. The other parts, not mentionedspecifically, correspond to the embodiments of FIGS. 1 and 2. Such anembodiment of the tracheal tube is particularly simple to produce from amanufacturing standpoint.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:
 1. A tracheal tube comprising, a hollow tubular bodyhaving a bore with an open tube end, an inflatable sealing cuff disposedaround said tubular body adjacent said tube end, at least one smalldiameter tube adjacent the wall of said hollow tubular body having anozzle portion terminating in a discharge jet centrally within the boreadjacent said open tube end for use in jet ventilation at highfrequencies above 600 cycles per minute, said small diameter tube havinga diameter of between 0.4 to 0.05 times the inside diameter of saidhollow tubular body, said discharge jet having a discharge opening whichis fixed relative to the open end at a spacing having a dimension withinfive times the inside diameter of said hollow tubular body, and a testline adjacent the wall of said hollow tubular body alongside said smalldiameter tube having a portion extending out of the wall and terminatingin an open mouth in the bore spaced upstream of said discharge jet.
 2. Atracheal tube as set forth in claim 1 further comprising a feed linewithin said hollow tubular body having an open end through the walladjacent said inflatable sealing cuff for inflating said inflatablesealing cuff.
 3. A tracheal tube as set forth in claim 2 wherein saidsmall diameter tube includes means for elastically supporting nozzleportion within said bore.
 4. A tracheal tube as set forth in claim 3wherein said elastic support means comprises a tubular nozzle carrierinterconnecting said small diameter tube and said nozzle portion.
 5. Atracheal tube comprising a hollow tubular body having an open tube end,an inflatable sealing cuff disposed around said tubular body adjacentsaid tube end, at least one small diameter tube at least partly embeddedwithin the wall of said hollow tubular body having a nozzle portionterminating in a discharge jet adjacent said open tube end for use injet ventilation at high frequencies above 600 cycles per minute, saidsmall diameter tube having a diameter of between 0.4 to 0.05 times theinside diameter of said hollow tubular body, said discharge jet having adischarge opening which is in the plane of the open tube end, and a testline at least partly embedded within the wall of said hollow tubularbody having a portion extending out of the wall and terminating in anopen mouth on the inner surface of the wall upstream of said dischargejet.
 6. A tracheal tube as set forth in claim 5 further comprising afeed line means at least partly embedded in the wall of said hollowtubular body having an open end through the wall adjacent saidinflatable sealing cuff for inflating said inflatable sealing cuff.
 7. Atracheal tube as set forth in claim 5 further wherein said open tube endis disposed in a plane extending obliquely relative to the longitudinalaxis of said hollow tubular body, and each of said discharge opening ofsaid discharge jet and said open mouth of said test line being disposedsubstantially in the plane of the open tube end.